Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Pop. | 2020 Pop. | Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Iowa City | 1 | 75,932 | 74,916 | 0.34% | 2,947 | 25.8 | City |
| Coralville | 2 | 24,017 | 22,333 | 1.78% | 1,896 | 12.7 | City |
| North Liberty | 3 | 21,626 | 20,500 | 1.32% | 2,270 | 9.5 | City |
| Tiffin | 4 | 6,893 | 4,620 | 8.98% | 1,614 | 4.3 | City |
| Solon | 5 | 3,229 | 3,039 | 1.48% | 2,021 | 1.6 | City |
| Lone Tree | 6 | 1,331 | 1,350 | -0.37% | 1,247 | 1.1 | City |
| University Heights | 7 | 1,175 | 1,223 | -1.01% | 4,519 | 0.3 | City |
| Hills | 8 | 924 | 866 | 1.54% | 1,124 | 0.8 | City |
| Swisher | 9 | 900 | 916 | -0.44% | 964 | 0.9 | City |
| Shueyville | 10 | 720 | 732 | -0.41% | 386 | 1.9 | City |
| Oxford | 11 | 708 | 716 | -0.28% | 765 | 0.9 | City |
| Frytown | 12 | 13 | 47 | -45.83% | 16 | 0.8 | CDP |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Iowa City is the largest city in Johnson County.
Frytown is the smallest city in Johnson County.
There are 12 cities in Johnson County, Iowa.